Pgf3beta

ABSTRACT

THE POSTAGLANDIN PGF3B, AND ITS SALTS, ESTERS, AND ALKYLANOATES ARE DISCLOSED. THESE NOVEL COMPOUNDS ARE USEFUL FOR A VARIETY OF PHARMACOLOGICAL PURPOSES, INCLUDING USE AS SMOOTH MUSCLE STIMULANTS AND AS CARDIOVASCULAR AGENTS.

United States Patent PGF Sune Bergstrom and Jan Sjovall, both KemiskaInstitufionen, Karslinska Institutet, Stockholm, Sweden No Drawing.Application Feb. 12, 1971, Ser. No. 115,108, now abandoned, which is a'continuation-impart of application Ser. No. 203,752, June 20,1962, nowPatent No. 3,598,858, which is a continuation-in-part of abandonedapplication Ser. No. 199,209, Apr. 9, 1962, which in turn is acontinuation-in-part of application Ser. No. 738,514, May 28, 1958, nowPatent No. 3,069,322. Divided and this application July 3, 1972, Ser.No. 268,442

Int. Cl. C07c 6'1 /32, 69/74 US. Cl. 260-468 D 7 Claims ABSTRACT OF THEnIscLosURE' The prostaglandin PGF and its salts, esters, and alkanoatesare disclosed. These novel compounds are useful for a variety ofpharmacological purposes, including use as smooth muscle stimulants andas cardiovascular agents.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisionof our copending application Ser. No. 115,108, filed Feb. 12, 1971, nowabandoned, which is a continuation-impart of our copending applicationSer. No. 203,752, filed June 20, 1962, now Pat. No. 3,598,858, which isa continuation-in-part of our copending application Ser. No. 199,209,filed Apr. 9, 1962, now abandoned, which is a continuation-in-part ofour copending application Ser. No. 738,514, filed May 28,1958, now Pat.No. 3,069,322.

DESCRIPTION OF THE INVENTION This invention relates to novelcompositions of matter, and is more specifically concerned with novelorganic compounds of the formula:

ice

mo H/ on,

R 0 H on: (v) wherein R and R are as defined above. Molecules of thecompounds encompassed by Formulas I, II, III, IV, and V each haveseveral centers of asymmetry. Formulas I, II, III, IV, and V areintended to represent optically active compounds each with the sameabsolute configuration as optically active prostaglandin E (PGE), laternamed prostaglandin E (PGE and obtained from certain mammalian tissues,for example, sheep vesicular glands. See our said Pat. No. 3,069,322.See also later publications, for example, Bergstrom et al., J. Biol.Chem. 238, 3555 (1963), Bergstrom et al., Pharmacol. Rev. 20, 1 (1968),and references cited in those.

In Formulas I, II, HI, IV, and V, a broken line attachment to thecyclopentane ring indicates a chain or group in alpha configuration,i.e., below the plane of the cyclopentane ring. A heavy solid lineattachment to the cyclopentane ring indicates a chain in betaconfiguration, i.e., above the plane of the cyclopentane ring. Theconfiguration of the side chain hydroxy in Formulas I, II, III, IV, andV is S.

A systematic name for the compound of Formula II wherein R and R arehydrogen is 3a,5fl-dihydroxy-2fl- [(3S)-3-hydroxyoctyl] 1acyclopentaneheptanoic acid. For convenience, this compound is designateddihydro- PGF A systematic name for the compound of Formula III wherein Rand R are hydrogen is 7-[3a,5B-dihydroxy- 23-[(3S)-3-hydroxy-trans-l-octenyl] 1a cyclopentyl]- h eptanoic acid. Forconvenience, this compound is designated PGF A systematic name for thecompound of Formula IV wherein R and R are hydrogen is 7-[3u,53-dihydroxy- 2 9[ (3S)-3-hydroxy-trans 1 octenyl] 1a cyclopentyl]cis-S-heptenoic acidLFor convenience, this compound is designated PGF Asystematic name for the compound of Formula V wherein R and R arehydrogen is 7-[3u,5/8dihydroxy- 2fi-[(3S) 3 hydroxy-trans 1,cis 5octadienyl]-lacyclopentyl]-cis-5-heptenoic acid. For convenience, thiscompound is designated PGF Dlhydro-PGF PGF PGF and PGF were previouslynamed dihydro-epi-PGF, epi-PGF, bisdehydro-epi- PGF, andtetradehydro-epi-PGF, respectively. See our said copending applicationSer. No. 203,752.

With regard to Formulas I, II, III, IV, and V, examples of hydrocarbylof not more than 13 carbon atoms are alkyl, e.g., methyl, propyl, hexyl,decyl; cycloalkyl, e.g., cyclopropyl, 2-butylcyclopropyl, cyclobutyl,cyclobutylmethyl, 3-pentylcyclobutyl, 2,2-dimethylcyclobutyl,cyclopentyl, 3-tert-butylcyclopentyl, 2-cyclopentylethyl, cyclohexyl,cyclohexylmethyl; aralkyl, e.g., benzyl, phenethyl, 1-phenylethy1,2-phenylpropyl, 3-phenylbutyl, 2-(1-naphthylethyl), benzhydryl; aryl,e.g., phenyl, p-tolyl, p-ethylphenyl, p-tert-butylphenyl, l-naphthyl;and such unsaturated moieties as allyl, crotyl, and propargyl.

3 With further regard to Formulas I, II, III, IV, and V, examples oflower alkanoyl are alkanoyl of 2 to 8 carbon atoms, inclusive, e.g.,acetyl, propionyl, butyryl, valeryl, hexanoyl, heptanoyl, octanoyl, andbranched chain isomeric forms of those, e.g., isobutyryl and isovaleryl.

The novel compounds of Formulas I, II, III, IV, and V, i.e., dihydro-PGFPGF PGF and PGF and their salts, esters, and alkanoates are extremelypotent in causing stimulation of smooth muscle as shown, for example, bytests on strips of guinea pig ileum, rabbit duodenum, or gerbil colon.These compounds are also highly active in potentiating other knownsmooth muscle stimulators, for example, oxytocic agents, e.g. oxytocinand the various ergot alkaloids including derivatives and analogsthereof. Accordingly, these novel Formulas I, II, III, IV, and Vcompounds are useful in place of or in combination with less than usualamounts of these and other known smooth muscle stimulators wheneversmooth muscle stimulation is needed to alleviate or prevent somephysiological condition in mammals, including humans, useful domesticanimals, pets, zoological specimens, and laboratory animals, forexample, mice, rabbits, rats, and monkeys. For example, these com poundscan be used to alleviate or prevent conditions of gastrointestinal atonyin mammals, including humans, e.g., paralytic ileus following anesthesiaand surgical operation or from other medical causes. For this purpose,the compound is administered parenterally, e.g., subcutaneously,intramuscularly or by intravenous injection or infusion in a dose range0.1 to 2 mg. per kg. of body weight per day, the exact dose depending onthe age, weight, and condition of the patient or animal, and thefrequency and route of administration. Small repeated doses areindicated when the aim is to prevent rather than alleviate the atony.

Another smooth muscle stimulatory area where these novel Formulas I, II,III, IV, and V compounds are useful in the control or prevention ofatonic uterine bleeding in mammals after abortion or delivery, to aid inthe expulsion of the placenta, and during the puerperium. For thispurpose, the compound is administered by intravenous infusionimmediately after abortion or delivery at a dose in the range about 0.1to about 100 g. per kg. of body weight per minute until the desiredeffect is obtained. Subsequent doses are given by intravenous,subcutaneous, or intramuscular injection or infusion during puerperiumin the range 0.1 to 2 mg. per kg. of body weight per day, again theexact dose depending on the age, weight, and condition of the patient oranimal.

In still another smooth muscle stimulatory area, these novel compoundsof Formulas I, II, III, -IV, and V are surprisingly useful in place ofoxytocin to induce labor in pregnant female animals, including man,cows, sheep, and pigs, at or near term, or in pregnant animals withintrauterine death of the fetus from about 20 weeks to term. For thispurpose, the compound is infused intravenously at a dose of 0.1 to 100g. per kg. of body weight per minute until at or near the termination ofthe second stage of labor, i.e., expulsion of the fetus. These compoundsare especially useful when the female is one or more weeks post-matureand natural labor has not started, or 12 to 60 hours after the membraneshave ruptured and natural labor has not yet started. An alternativeroute of administration is oral.

The novel compounds of Formulas I, II, III, IV, and V are also usefulfor controlling the reproductive cycle in ovulating female mammals,including humans and animals such as monkeys, rats, rabbits, dogs,cattle, and the like. By the term ovulating female mammals is meantanimals which are mature enough to ovulate but not so old that regularovulation has ceased. For that purpose, PGF for example, is administeredsystemically at a dose level in the range 0.1 mg. to about 20 mg. perkg. of body weight of the female mammal, advantageously during a span oftime starting approximately at the time of ovulation and endingapproximately at the time of menses or just prior to menses.Intravaginal and intrauterine are alternative routes of administration.Additionally, expulsion of an embryo or a fetus is accomplished bysimilar administration of the compounds during the first third of thenormal mammalian gestation period.

The novel compounds of Formulas I, II, III, IV, and V are also useful inmammals, including man, as nasal decongestants. For this purpose, thecompounds are used in a dose range of about 10 pg. to about 10 mg. perml. of a pharmacologically suitable liquid vehicle or as an aerosolspray, both for topical application. The novel Formulas I, II, III, IV,and V compounds also lower systemic arterial blood pressure inanesthetized (pentobarbital sodium) pentolinium-treated rats withindwelling aortic and right heart cannulas. Accordingly, these novelcompounds are useful as hypotensive agents to reduce blood pressure inmammals, including man. For this purpose, the compounds are administeredby intravenous infusion at the rate about 0.1 to about g. per kg. ofbody weight per minute, or in single or multiple doses of about 100 ,ug.to 5 mg. per kg. of body weight total per day.

The novel Formulas I, II, III, IV, and V compounds of this invention areused for the purposes described above in the free acid form, in esterform, in alkanoate form, in ester-alkanoate form, or inpharmacologically acceptable salt form. When the ester ofester-alkanoate form is used, the ester moiety is any of those withinthe definition of R However, it is preferred that the R moiety notcontain olefinic or acetylenic unsaturation. More preferred are alkylesters wherein the alkyl moiety contains one to 8 carbon atoms,inclusive. Especially preferred are alkyl of one to 4 carbon atoms,inclusive. Of those alkyl, methyl and ethyl are especially preferred foroptimum absorption of the compound by the body or experimental animalsystem.

Examples of alkyl of one to 4 carbon atoms are methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl and tert-butyl. Examples of alkylof one to 8 carbon atoms are those mentioned above, and also pentyl,hexyl, heptyl, octyl, and branched chain isomers thereof, e.g.,2-ethylhexyl.

When the alkanoate or ester-alkanoate form is used, the alkanoyl moietyis any of those within the definition of R However, acetyl is especiallypreferred for optimum absorption of the compound by the body orexperimental animal system. In Formulas I, II, III, IV, and V, it isintended that all R; be hydrogen or that all be alkanoyl.

Pharmacologically acceptable salts of the Formulas I, II, III, IV, and Vcompounds wherein R is hydrogen useful for the purposes described aboveare those with pharmacologically acceptable metal cations, ammonium,amine cations, or quaternary ammonium cations.

Especially preferred metal cations are those derived from the alkalimetals, e.g., lithium, sodium and potassium, and from the alkaline earthmetals, e.g., magnesium and calcium, although cationic forms of othermetals, e.g., aluminum, zinc, and iron, are within the scope of thisinvention.

Pharmacologically acceptable amine cations are those derived fromprimary, secondary, or tertiary amines. Ex-

amples of suitable amines are methylamine, dimethylamine,trimethylamine, ethylamine, dibutylamine, triisopropylamine,N-methylhexylamine, decylamine, dodecylamine, allylamine, crotylarnine,cyclopentylamine, dicyclohexylamine, benzylamine, dibenzylamine,u-phenylethylamine, fl-phenylethylamine, ethylenediamine,diethylenetriamine, and like aliphatic, cycloaliphatic, and araliphaticamines containing up to and including about 18 carbon atoms, as well asheterocyclic amines, e.g., piperidine, morpholine, pyrrolidine,piperazine, and loweralkyl derivatives thereof, e.g.,l-methylpiperidine, 4-ethylmorpholine, l-isopropylpyrrolidine,Z-methylpyrrolidine, 1,4-dimethylpiperazine, 2-methylpiperidine, and thelike, as well as amines containing water-solubilizing or hydrophilicgroups, e.g., mono-, di-, and triethanolamine, ethyldiethanolamine,N-butylethanolamine, Z-amino-l-butanol, 2-amino-2-ethyl-1,3-propanediol,2-amino-2-methyll propanol, tris(hydroxymethyl)aminomethane,N-phenylethanolamine, N (ptert-amylphenyl)diethanolamine, galactamine,N-methylgluca-mine, N-methylglucosamine, ephedrine, phenylephrine,epinephrine, procaine and the like.

Examples of suitable pharmacologically acceptable quaternary ammoniumcations are tetramethylammonium, tetraethylammonium,benzyltrimethylam-monium, phenyltriethylamrnonium, and the like.

When the novel Formulas I, II, III, IV, and V compounds are used forintravenous injection or infusion, sterile aqueous isotonic solutionsare preferred. For that purpose, it is preferred because of increasedwater solubility that R in Formulas I, H, 111, IV, and V be hydrogen ora pharmacologically acceptable cation. For subcutaneous or intramuscularinjection, sterile solutions or suspensions of the acid, salt, or esterin aqueous or nonaqueous media are used. Tablets, capsules, and liquidpreparations such as syrups, elixers, and simple solutions, with theusual pharmaceutical carriers, are used for oral or sublingualadministration. For rectal, vaginal, or intrauterine administration,suppositories, lavage and douche preparations, and solutions as such orcontained in a sponge, all prepared by methods known in the art, areused.

Dihydro-PGF (Formula II, R and R =H) is prepared by catalytichydrogenation of PGF PGF or PGF (Formulas III, IV, and V, respectively,R and R =H). Similarly, the esters and alkanoates of dihydro- PGF areprepared by catalytic hydrogenation of the corresponding esters andalkanoates of PGF PG1F and PGF3B.

These catalytic hydrogenations are carried out by methods known in theart for saturating olefinic compounds. Suitable hydrogenation catalystsare those containing platinum or palladium alone or on an inert carrier.Especially preferred catalysts are the finely-divided platinum metalobtained by prior or simultaneous hydrogenation of the platinum oxideknown as Adams catalyst (Org. Syn. Coll. vol. 1, 463 (1941), or finelydivided palladium metal supported on a carbon carrier, advantageouslycontaining about 5 percent palladium by weight. Another useful catalystfor this purpose is rhodium metal (5%) on alumina. Suitable liquidhydrogenation diluents are ethanol, ethanol containing a smallpercentage of acetic acid, i.e., about one to apout 15 percent by volumeof acetic acid, dioxane, and ethyl acetate. Hydrogenation pressuresranging from about atmospheric to about 50 p.s.i., and hydrogenationtemperatures ranging from about to about 100 C. are preferred. When PGFor one of its esters or alkanoates is used, the hydrogenation process isstopped after absorption of one equivalent of hydrogen, and theresulting dihydro product is isolated from the reaction mixture byconventional methods, for example, removal of the catalyst by filtrationor centrifugation, followed by evaporation of the liquid diluent. WhenPGF or PGF or their esters or alkanoates are used for this catalytichydrogenation, additional hydrogen will be necessary for completesaturation of all of the carbon-carbon double ponds, two equivalents inthe case of the PGF reactants and three equivalents in the case of theP-GF reactants.

These hydrogenations will also saturate any olefinic or acetylenicunsaturation present in the hydrocarbyl portion of the PGF PGF or PGFreactant. Enough additional hydrogen should be used to saturate thoseother double and triple bonds to insure complete saturation of thedouble bonds in the prostaglandin side chains.

If a Formula II dihydro-IGF ester with an olefinic or acetylenic Rmoiety is desired, that is made by esterification of the dihydro-PGFacid.

Other reactants for producing dihydro-PGF and its esters are thecompounds known as dihydro-PGE and its esters. Similarly, P'GF and itsesters are prepared from the compounds known as PGE and its esters, PGFand its esters are prepared from the compounds known as PGE and itsesters, and PGF and its esters are prepared from the compounds known asPGE and its esters. The structural formulas of these dihydro-PGE (VI),PGE (VII), PGE (VIII), and PGE (IX) reactants are (VII) (VIII) (I ThesedihydroPGE PGE PGE and PGE acid and ester react-ants are prepared asdescribed in our said Pat. No. 3,069,322 and in our said copendingapplication Ser. No. 203,752.

In these transformations of these PGE-type compounds to the desired andnovel PGF -type acids and esters of this invention, the ring carbonyl ofthe PGE-type reactant is reduced to a secondary alcohol group withsodium borohydride in the presence of an inert diluent, advantageously,methanol. A mixture of two isomeric secondary alcohols is produced byeach of these ring carbonyl reductions. For example, ring carbonylreduction of PGE gives a mixture of PGF (Formula 111, R=H) and theisomeric compound known as PGF The latter compound has the structuralformula:

H OH (X) The preparation of PGF by another method is described in oursaid Pat. No. 3,069,322. PGF is separated from PGF by chromatography asdescribed hereinafter. In a similar manner, ring carbonyl reduction ofdihydro-PGE give a mixture of dihydro-PGF and dihydro-PGF ring carbonylreduction of PGE gives a mixture of PGF and PGFz... and ring carbonylreduction of PGE gives a mixture of PGF;;, and PGF Similarly, ringcarbonyl reduction of the esters of dihydro-PGE PGE PGE and PGE givescorresponding mixtures of the PGF -type and PGF -type esters. Thecomponents of each of these mixtures of PGF -type and PGF -type acids oresters are separated by chromatography as described hereinafter.

For these ring carbonyl reductions, a cold solution or suspension ofsodium borohydride in methanol is added to a cold solution of thePGE-type reactant in methanol. The mixture is maintained cold for about10 to 60 minutes, and is then maintained at about 25 C. for about one totwo hours. The resulting mixture of PGF -type and PGF -type products isthen isolated and separated into its components as describedhereinafter. About three parts by weight of sodium borohydride is usedfor each part by weight of the PGE-type reactant. Suitable amounts ofmethanol are about 100 ml. for each gram of the PGE- type reactant andabout 100 ml. for each gram of the sodium borohydride. A suitable coldtemperature is about C.

When dihydro-PGF (Formula II, R=H), PGF (Formula IH, R=H), PGF (FormulaIV, R=H) or PGF (Formula V) has been prepared by ring carbonyl reductionof the corresponding PGE-type reactant, or when dihydro-PGF, has beenprepared by catalytic hydrogenation as described above, and ahydrocarbyl ester is desired for one of the above-describedpharmacological purposes, those acids are esterified by procedures knownin the art. Illustratively, the alkyl esters are prepared by reaction ofthe acid with the appropriate diazohydrocarbon. For example, whendiazomethane is used, the methyl esters are produced. Similar use ofdiazoethane, diazobutane, and 1-diazo-2-ethylhexane, for example, givesthe ethyl, butyl, and 2-ethylhexyl esters, respectively.

Esterification with diazohydrocarbons is carried out by mixing asolution of the diazohydrocarbon in a suitable inert solvent, preferablydiethyl ether, with the acid reactant, advantageously in the same or adifferent inert diluent. After the esterification reaction is complete,the solvent is removed by evaporation, and the ester purified if desiredby conventional methods, preferably by chromatography. It is preferredthat contact of the acid reactants with the diazohydrocarbon be nolonger than necessary to effect the desired esterification, preferablyabout one to about ten minutes, to avoid undesired molecular changes.Diazohydrocarbons are known in the art or can be prepared by methodsknown in the art. See, for example, Organic Reactions, John Wiley &Sons, Inc., New York, N.Y., vol. 8, pp. 389-394 (1954).

An alternative method for esterification of the carboxyl moiety of thesePGF -type acids comprises transformation of the free acid to thecorresponding silver salt, followed by interaction of that salt with analkyl iodide. Examples of suitable iodides are methyl iodide, ethyliodide, butyl iodide, isobutyl iodide, tert-butyl iodide, and the like.The silver salts are prepared by conventional methods, for example, bydissolving the acid in cold dilute aqueous ammonia, evaporating theexcess ammonia at reduced pressure, and then adding the stoichiometricamount of silver nitrate.

When a trialkanoate of one of the Formula I, II, III, IV, or V PGF -typeacids or esters (all R =lower alkanoyl) is desired for one of theabove-described pharmacological purposes, it is prepared by reacting thecorresponding trihydroxy compounds, i.e. (all R =hydrogen), with analkanoic anhydride corresponding to an alkanoic acid of 2 to 8 carbonatoms, inclusive. Examples of these anhydrides are acetic anhydride,proponic anhydride, butyric anhydride, valeric anhydride, hexanoicanhydride, heptanoic anhydride, octanoic anhydride, and isomeric formsof those.

This reaction leading to these trialkanoates is advantageously carriedout by mixing the hydroxy compound and the acid anhydride, preferably inthe presence of a tertiary amine such as pyridine or triethylamine. Asubstantial excess of the anhydride is used, preferably about 10 to 10,-000 moles of anhydride per mole of the hydroxy compound reactant. Theexcess anhydride serves as a reaction diluent and solvent. An inertorganic diluent, for example, dioxane, can also be added. It ispreferred to use enough of the tertiary amine to neutralize thecarboxylic acid produced by the reaction, as well as any free carboxylgroups present in the hydroxy compound reactant.

The reaction is preferably carried out in the range about 0 to about C.The necessary reaction time will depend on such factors as the reactiontemperature, and the nature of the anhydride and tertiary aminereactants. With acetic anhydride, pyridine, and a 25 C. reactiontemperature, a 12 to 24-hour reaction time is used.

The desired trialkanoate is isolated from the reaction mixture byconventional methods. For example, the excess anhydride is decomposedwith water, and the resulting mixture acidified and then extracted witha solvent such as diethyl ether. The desired trialkanoate is recoveredfrom the diethyl ether extract by evaporation. The trialkanoate is thenpurified by conventional methods, advantageously by chromatography.

Each of the Formula I, II, III, IV, and V PGF -type acids (R ishydrogen) is transformed to pharmacologically acceptable salts byneutralization with appropriate amounts of the corresponding inorganicor organic base, examples of which correspond to the cations and amineslisted above. These transformations are carried out by a variety ofprocedures known in the art to be generally useful for the preparationof inorganic, i.e., metal or ammonium, salts, amine acid addition salts,and quaternary ammonium salts. The choice of procedure depends in partupon the solubility characteristics of the particular salt to beprepared. In the case of the inorganic salts, it is usually suitable todissolve the acid in water containing the stoichiometric amount of ahydroxide, carbonate, or bicarbonate corresponding to the inorganic saltdesired. For example, such use of sodium hydroxide, sodium carbonate, orsodium bicarbonate gives a solution of the sodium salt of the prostanoicacid derivative. Evaporation of the water or addition of awater-miscible solvent of moderate polarity, for example, a loweralkanol or a lower alkanone, gives the solid inorganic salt if that formis desired.

To produce an amine salt, the acid is dissolved in a suitable solvent ofeither moderate or low polarity. Examples of the former are ethanol,acetone, and ethyl acetate. Examples of the later are diethyl ether andbenzene. At least a stoichiometric amount of the amine corresponding tothe desired cation is then added to that solution. If the resulting saltdoes not precipitate, it is usually obtained in solid form by additionof a miscible diluent of low polarity or by evaporation. If the amine isrelatively volatile, any excess can easily be removed by evaporation. Itis preferred to use stoichiometric amounts of the less volatile amines.

Salts wherein the cation is quaternary ammonium are produced by mixingthe acid with the stoichiometric amount of the corresponding quaternaryammonium hydroxide in water solution, followed by evaporation of theWater.

The invention can be more fully understood by the following examples.

Example 1 PGF A solution of 100 mg. of PGE dissolved in 10 ml. ofmethanol is cooled in an ice bath. A chilled solution of 300 mg. ofsodium borohydride in 35 ml. of methanol is added. After 20 minutes at 0C., the mixture is left at room temperature for one hour. Water is addedand most of the methanol is taken off in vacuo. After acidification withhydrochloric acid, the aqueous phase is extracted three times withether, and the combined ether extract is washed with water and broughtto dryness at room temperature. The residue is subjected to reversedphase partition chromatography on hydrophobic kieselguhr using 43percent aqueous methanol as the mobile phase and equal parts ofisooctanol and r chloroform as the stationary phase. The dried etherextract is placed on the column with 16 ml. of the stationary phase anddeveloped with 1200 ml. of mobile phase. The 475-650 ml. fractions arecombined and taken to dryness and-crystallized from ethylacetate-pentane. The yield is 37 mg. of PGF M.P. 101 C. The 300-425 ml.fractions are processed in a like manner and crystallized from ethylacetatepentane to yield 47 mg. of crystalline PGF having a melting pointof 128 C. The paper chromatographic mobilities relative to PGE, ondescending paper chromatography with ethylene chloride-heptane (1:1) asmoving phase and 70% aqueous acetic acid as stationary phase are PGE,(1.00), PGF (0.64), and PGF (0.44).

Example 2 PGF Following the procedure of Example 1 but replacing PGEwith PGE a mixture of PGF and PGF is obtained. The PGF and PGF areseparated as described in Example 1. The paper chromatographicmobilities relative to PGE determined as describedin Example 1 are PGE(1.00), PGE (0.90), PGF (0.60), and PGF (0.39). The PGF and PGF obtainedby this process are sufficiently pure to give substantially ideal curveson partition chromatography, using an ethylene chloride: heptanezaceticacidzwater (1'5 :15 :6t'4)' solvent system, that is, curves typical ofthe essentially pure compounds.

Example. 3 PGF Example 4 PGF A suspension of sodium borohydride (900mg.) in 105 ml. of cold methanol is added in several portions duringthree minutes with stirring to an ice-cold solution of PGE (300 mg.) in30 ml. of methanol. After 20 minutes at C., the mixture is allowed towarm to 25 C., and is maintained there for one hour. The mixture is thenconcentrated under reduced pressure, diluted with water, acidified, andextracted with diethyl ether. The extract is washed with water, dried,and evaporated. The residue is subjected to reversed phasechromatography over siliconized diatoma-ceous earth (Gas-Chrom CLZ100-200 mesh with mobile and stationary phase composed of the upper andlower phase, respectively, derived from 516 ml. of methanol, 684 ml. ofwater, 60 ml. of isooctanol, and 60 ml. of chloroform). The eluatefractions are analyzed by thin layer chromatography with the A-IXsystem. The PGF is eluted first, followed by the PCP Eluate fractionscontaining only PGF are combined and evaporated. Eluate fractionscontaining only PG-F are combined and evaporated. Those eluate fractionscontaining both compounds are combined and evaporated, and the resultingresidue is chromatographed on acid-washed silica gel, eluting first withethyl acetate, and then with ethyl acetate containing 2% methanol and 1%acetic acid. The eluate fractions are analyzed as above. The PGF iseluted first. Additional PGF and PGF are thereby obtained. After twocrystallizations from a mixture of ethyl acetate and Skellysolve B (amixture of isomeric hexanes), the PGF has M.P. 101-103 C.; the PGF,, hasM.P. 127-'130 C.

10 Example 5 PGF Following the procedure of Example 4, PGE (4.00 g.) isreduced with sodium borohydride to a mixture of PGF and PGFCrystallization from ethyl acetate gives 2.8 g. of a crystallinefraction rich in PGF and a filtrate containing 1.2 'g. of a fractionrich in PGF Each fraction is chromatographed separately on acid-washedsilica gel. The PGF part from each fraction is eluted with ethyl acetatecontaining 2% methanol and 1% acetic acid. The PGF part from each isthen eluted with ethyl acetate containing 4% methanol and 2% aceticacid. Eluate fractions are analyzed by thin layer chromatography withthe A-IX system. Eluate fractions containing only PGF are combined andevaporated to give 1.77 g. of PGF Eluate fractions containing only PGFare combined and evaporated to give 2.10 g. of PGF PGF is a viscouscolorless oil which is crystallized from diethyl ether; M.P. 30-35 C.;infrared absorption (neat) at 3320, 2640, 1710, 1295, 1260, 1245, 1120,1080, 1055, 1025, and 975 cm.- PGF is crystallized as colorless prismsfrom ethyl acetate; M.P. 96.597 C., infrared absorption (mineral oilmull) at 3440, 3260, 3220, 2720, 2660, 2600, 1697, 1275, 1250, 1200,1040, 977, and 968 cmr- Example 6 PGF methyl ester To a dry ethersolution of one milligram of PGE, is added aslight excess ofdiazomethane prepared in ether from four micromoles ofnitrosomethylurethane. The reaction mixture is allowed to stand about 5minutes, and the ether and excess diazomethane are then distilled off.On distillation to dryness, PGF methyl ester is obtained; M.P. l07-108C.

Example 7 PGF methyl ester Following the procedure of Example 6, PGF istransformed to its methyl ester.

Example 8 PGF methyl ester Following the procedure of Example 6, PGF istransformed to its methyl ester.

Example 9 PGF methyl ester triacetate Example 10 PGF methyl estertriacetate Following the procedure of Example 9, PGF methyl ester istransformed to the triacetate.

Example 11 PGF Methyl-ester triacetate Following the procedure ofExample 9, PGF methyl ester is transformed to the triacetate.

The methyl esters and methyl ester triacetates of Examples 6, 7, 8, 9,l0, and 11 have the following retention times:

Methyl Methyl ester P GFp-type ester tri acetate Conditions: Flashheater at 220 C.; Column temperature 200 C.; Column pressure 1.0 kg./cm.Column 6 ft. x 5 mm. packed with 0.5% QF-l (Dow Corning Corp.) on GasChrom P (Applied Science Laboratory,

Inc.) as described by Vanden Heuvel et al., I. Am. Chem. Soc. 83, 1513(1961).

Example 12 dihydro-PGF methyl ester A solution of dihydro-PGF (6 mg.) ina mixture of methylene chloride and methanol is treated with excessdiazomethane in diethyl ether and allowed to stand 15 minutes. Thereaction mixture is evaporated to give dihydro-PGF methyl ester; M.P.63-65 C.

Following the procedures of Example 6 or 12 but replacing diazomethanewith diazoethane, diazobutane, l-diazo-2-ethylhexane,cyclohexyldiazomethane, and phenyldiazomethane, and using each in turn,dihydro-PGF PGF PGF and PGF there are obtained the ethyl, butyl,2-ethy1hexyl, cyclohexylmethyl, and benzyl esters of each of those PGF,compounds.

Also following the procedure of Example 9 but using propionic anhydride,isobutyric anhydride, and hexanoic anhydride each in place of aceticanhydride, and using each in turn, dihydro-PGF PGF,,, PGF PGF andmethyl, ethyl, butyl, 2-ethylhexyl, cyclohexylmethyl, and benzyl estersof each of those PGF, compounds, there are obtained the tripropionates,triisobutyrates, and trihexanoates of each of these PGF, acids andesters. Also following the procedure of Example 9, the triacetates ofthese other PGF, acids and esters are obtained.

Example 13 dihydro-PGF A solution of 0.200 g. of PG-F in 50 ml. of 95%ethanol is hydrogenated at atmospheric pressure using 0.100 g. of 5%rhodium-on-alumina catalyst. When hydrogen uptake has ceased, themixture is filtered and the filtrate is evaporated. The residue ischromatographed over 20 g. of acid-washed silica gel wet-packed in 75%ethyl acetate in benzene, eluting with 100 ml. of 75 ethyl acetate inbenzene, 100 ml. of ethyl acetate, and 220 ml. of 2% methanol and 1%acetic acid in ethyl acetate, taking 20 ml. fractions. Fractions 13-21are combined and evaporated to a residue (0.19 g.) which is crystallizedfrom anhydrous ether to give dihydr0-PGF with substantially the samephysical properties as the product of Example 12.

12 What is claimed is: 1. A compound of the formula:

wherein R is hydrogen or hydrocarbyl of not more than 13 carbon atoms,and wherein all R are hydrogen or all R are lower alkanoyl, andpharmacologically acceptable salts thereof when R is hydrogen.

2. A compound according to claim 1 wherein R and all R are hydrogen.

3. A compound according to claim 1 wherein R is alkyl of one to 8 carbonatoms, inclusive, and all R are hydrogen.

4. A compound according to claim 1 wherein R is methyl and all R arehydrogen.

5. A compound according to claim 1 wherein R is alkyl of one to 8 carbonatoms, inclusive, and all R are lower alkanoyl.

6. A compound according to claim 1 wherein R is alkyl of one to 8 carbonatoms, inclusive, and all R are acetyl.

7. A compound according to claim 1 wherein R is methyl and all R areacetyl.

References Cited Linn et al.: Biochemical Pharmacology 8, 339 (1961).

LORRAINE A. WEINBERGER, Primary Examiner R. GERSTL, Assistant ExaminerUS. Cl. X.R.

260-211 R, 147.2 R, 268 R, 293.1 S, 326.3, 410, 429.9, 430, 439, 448 R,488 R, 501.1, 501.15, 501.17, 501.2, 514 D UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent: No. 5,804,880 Dated April 16, 197ilnventol-(s) Sune Bergstrom and Jan Sjoval I It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Column 1, l ine 72, Formula should be numbered l l I Column 2, lines10-16, that portion of the formula reading I Z I Column 4, line 29,"ester of ester-alkanoate" should read ester or ester-al kanoate Column5, l ine 67, "carbon-carbon double ponds," should read carbon-carbondouble bonds, Column 9, lines 336%, "replacing PGE with PGF should readreplacing PGE with PGE Signed and Scaled this ninth Day f August 1977[SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Attesli'lg ff Commissioner of Patents andTrademarks

